TY - JOUR
T1 - Synthesis and crystal structure of 2,4-dihydro-4-[(5-hydroxy-3-methyl-1-phenyl-1H-pyrazol-4-yl)imino]-5-methyl-2-phenyl-3H-pyrazol-3-one and its copper (II) complex
AU - Cerchiaro, G.
AU - Da Costa Ferreira, A. M.
AU - Teixeira, A. B.
AU - Magalhaes, H. M.
AU - Cunha, A. C.
AU - Ferreira, V. F.
AU - Santos, L. S.
AU - Eberlin, M. N.
AU - Skakle, Janet Mabel Scott
AU - Wardell, S. M. S. V.
AU - Wardell, J. L.
PY - 2006
Y1 - 2006
N2 - 2-Diazo-3-methyl-1-phenyl-5-pyrazolone (2) and 2,4-dihydro-4-[(5-hydroxy-3-methyl-1-phenyl-1H-pyrazol-4-yl)imino]-5-methyl-2-phenyl-3H-pyrazol-3-one (3) were obtained in a one-pot reaction from 3-methyl-1-phenylpyrazol-5-one (1), mesyl azide, and K2CO3 in MeOH or CH2Cl2 solution. NMR, IR and ESI mass spectra as well as the crystal structure are reported for red colored 3. The crystal structure determined at 150 K reveals that the corresponding bonds in the two phenylpyrazol-5-one moieties in each of the two independent "U" shaped molecules have essentially the same lengths, with an extensive delocalization in the central O-C-C-N-C-C-O fragment of the molecule. In particular, the hydrogen atom, formally a part of a hydroxyl group, is found near-midway [01-HY and 011-HY = 1.24(4) and 1.19(4) angstrom, in molecule 1, and O21-HX and O31-HY = 1.203(4) and 1.19(4) angstrom, in molecule 2] between the two oxygen atoms (formally in a carbonyl and a hydroxy group), with near linear O-H-O bond angles of 173.8(4)degrees and 172.7(4)degrees in the two independent molecules. All C-O bond lengths are in the narrow range of 1.27](3)-1.288(3) angstrom. Further, since this compound shows different coordinating groups, its binding ability towards copper(II) ions was investigated. A dark red complex 4, obtained by reaction of 3 with copper(II) ions at stoichiometric ratio, was characterized as a neutral 1: 1 species, [3:CuCl,], involving tautomeric forms, by ESI-MS, ESI-MS/MS, IR, UV/Vis and EPR spectra. Interestingly, copper coordination to ligand 3 occurs solely by oxygen atoms, in spite of the presence of nitrogen donor centers. The deprotonation of 4 was monitored by UV/Vis, and a corresponding pKa value was determined as (5.6 +/- 0.2). (c) 2006 Elsevier Ltd. All rights reserved.
AB - 2-Diazo-3-methyl-1-phenyl-5-pyrazolone (2) and 2,4-dihydro-4-[(5-hydroxy-3-methyl-1-phenyl-1H-pyrazol-4-yl)imino]-5-methyl-2-phenyl-3H-pyrazol-3-one (3) were obtained in a one-pot reaction from 3-methyl-1-phenylpyrazol-5-one (1), mesyl azide, and K2CO3 in MeOH or CH2Cl2 solution. NMR, IR and ESI mass spectra as well as the crystal structure are reported for red colored 3. The crystal structure determined at 150 K reveals that the corresponding bonds in the two phenylpyrazol-5-one moieties in each of the two independent "U" shaped molecules have essentially the same lengths, with an extensive delocalization in the central O-C-C-N-C-C-O fragment of the molecule. In particular, the hydrogen atom, formally a part of a hydroxyl group, is found near-midway [01-HY and 011-HY = 1.24(4) and 1.19(4) angstrom, in molecule 1, and O21-HX and O31-HY = 1.203(4) and 1.19(4) angstrom, in molecule 2] between the two oxygen atoms (formally in a carbonyl and a hydroxy group), with near linear O-H-O bond angles of 173.8(4)degrees and 172.7(4)degrees in the two independent molecules. All C-O bond lengths are in the narrow range of 1.27](3)-1.288(3) angstrom. Further, since this compound shows different coordinating groups, its binding ability towards copper(II) ions was investigated. A dark red complex 4, obtained by reaction of 3 with copper(II) ions at stoichiometric ratio, was characterized as a neutral 1: 1 species, [3:CuCl,], involving tautomeric forms, by ESI-MS, ESI-MS/MS, IR, UV/Vis and EPR spectra. Interestingly, copper coordination to ligand 3 occurs solely by oxygen atoms, in spite of the presence of nitrogen donor centers. The deprotonation of 4 was monitored by UV/Vis, and a corresponding pKa value was determined as (5.6 +/- 0.2). (c) 2006 Elsevier Ltd. All rights reserved.
KW - pyrazole derivatives
KW - copper complex
KW - structural characterization
KW - EPR and NMR spectroscopy
KW - ESI mass spectrometry
KW - BETA-DIKETONE INTERACTIONS
KW - ENOL TAUTOMERS
KW - HYDROGEN-BOND
KW - SCHIFF BASE
KW - CARBOHYDRATE OXIDATION
KW - BIOLOGICAL EVALUATION
KW - MOLECULAR-STRUCTURE
KW - MAGNETIC-PROPERTIES
KW - ORGANIC-SYNTHESIS
KW - CU(II) COMPLEXES
U2 - 10.1016/j.poly.2006.01.002
DO - 10.1016/j.poly.2006.01.002
M3 - Article
SN - 0277-5387
VL - 25
SP - 2055
EP - 2064
JO - Polyhedron
JF - Polyhedron
ER -